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Encephalitis

Topic Overview

What is encephalitis?

Encephalitis is
inflammation of the brain. This inflammation can cause symptoms such as confusion, a
fever, a bad headache, and a stiff neck. Sometimes it leads to symptoms like
seizures and personality changes. It can also cause long-term problems, such as trouble with speech or memory.

Encephalitis is uncommon, but it can be deadly. If you think you have
symptoms of encephalitis, see a doctor right away.

What causes encephalitis?

Infection with a virus is the main cause of encephalitis. Different types of viruses can cause the illness. For example, West Nile virus can cause encephalitis when a person is bitten by an infected mosquito. Another type is the herpes simplex virus, which is the same virus that causes cold sores and genital herpes. A mother who is infected with the herpes virus can also pass the virus to her baby. If this happens and the baby gets encephalitis, it is very serious.

Encephalitis also can be caused by bacteria or by a parasite, such as the one that causes toxoplasmosis. In rare cases, encephalitis can be caused by a fungus.

But most people who get these types of infections don't get encephalitis.

If you think that you or your child has encephalitis, call your doctor right away.

Early on, symptoms of encephalitis may be like
those of
meningitis. This is a serious viral or
bacterial illness that causes swelling of the tissues
around the brain and spinal cord.

How is encephalitis diagnosed?

Your doctor will ask questions about
your past health and your symptoms. He or she will likely order tests to
confirm the diagnosis. These may include:

Spinal fluid analysis. By doing a lumbar puncture (also called a spinal tap), your doctor can check the spinal fluid for an increase in
white blood cells and
protein. The bacteria, virus, parasite, or fungus causing the encephalitis also may be found in the spinal fluid.

Imaging tests. An
MRI or CT scan, which takes pictures of the inside of your
body, may show bleeding, swelling, or other changes in the brain. See a picture of a brain with encephalitis.

Electroencephalogram (EEG). This test can measure the electrical signals in the brain.
It may show a change related to the illness.

Blood tests. These tests can show what type of virus is causing encephalitis.

How is it treated?

If you have encephalitis, you
will need to be treated in a hospital. Your treatment will depend on your
symptoms and the cause of your illness. You may be treated right away with an antiviral medicine, such as acyclovir. Antiviral medicine may make symptoms less severe, especially if you get the medicine right
away. If the
doctor thinks that your symptoms are caused by bacteria, rather than by a virus, he or she may treat you with antibiotics.

You will also get care to ease
your symptoms and allow your body to heal on its own. This is called supportive
care. You may take medicines to reduce pain and fever or to stop seizures. In
some cases, you may need a machine called a
ventilator to help you breathe.

After you are out of the hospital, it may take several weeks, months, or even longer to
fully recover from your symptoms. You can take care of yourself by eating well and getting plenty of rest. Follow your doctor's instructions on how much fluid to drink. If your doctor says it's okay, you can take nonprescription pain relievers for headaches. These include acetaminophen and
nonsteroidal anti-inflammatory drugs (NSAIDs) like
naproxen, ibuprofen, or aspirin. Do not give aspirin to anyone younger than 20 because of the risk of
Reye syndrome. Be safe with medicines. Read and follow all instructions on the label.

Some people have long-term problems. If you have muscle weakness or problems with coordination, you may need physical therapy. If you have speech or memory loss, you may need speech therapy or occupational therapy.

Can encephalitis be prevented?

Your chance of
getting encephalitis is low. But there are things you can do to reduce your chances even
more.

Make sure that you and your children get shots (vaccines)
against measles, mumps, rubella, chickenpox, and the flu.

Avoid areas where there has been an outbreak of viral
encephalitis. If you can't avoid these areas, prevent mosquito bites with these tips:

Stay indoors at dawn, at dusk, and in the early evening, when mosquitoes are most active.

Wear long-sleeved shirts and long pants whenever you are outdoors and are likely to be where mosquitoes are.

Use insect repellent with DEET (N,N-diethyl-meta-toluamide). The repellent is available in varying strengths up to 100%. In young children, use a preparation containing less than 24% strength, because too much of the chemical can be absorbed through the skin.

Spray clothing with an insect repellent containing permethrin or DEET, because mosquitoes may bite through thin clothing. DEET can damage plastic items, such as watch crystals or eyeglass frames, and some synthetic fabrics. You also can use natural products such as soybean-based Bite Blocker.

Avoid applying repellent to the hands of children. Repellents may irritate the eyes and mouth.

Whenever you use an insecticide or insect repellent, be sure to read and follow the directions for use.

Do not keep open containers of water near your house. Standing water is a breeding place for mosquitoes.

If you are taking a long trip to the Far East or to central or eastern Europe, talk to your doctor about getting vaccinated against certain types of mosquito- or tick-borne encephalitis. For example, there is a vaccine for Japanese encephalitis. Getting vaccinated is especially important if you are going to a rural area.

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